Voltage stabilizing tube



1950 F. A. VAN BECKUM 2,534,389

VOLTAGE STABILIZING TUBE Filed July 2, 194a ANCZDICAZZLYPOLLSHED NICKEL CAZWODE 50.212112 mwmrcws'ANwMz/s mBECKUM.

I N V EN TOR.

AGENT.

Patented Dec. 19, 1950 Fredericus Antonius van Beckum, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn as trustee Application July 2, 1946, Serial No. 681,125 In the Netherlands March 15, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires March 15, 1963 1 Claim. 1

This invention relates to a voltage stabilisation tube i. e. a glow discharge tube which is used for keeping constant direct voltage. The discharge in a stabilisation tube is a glow discharge in the range of the normal cathode drop. The surface of the cathode covered by the discharge is practically proportional to the current. When the tube has only one cathode and one anode only one constant voltage can be taken off, but when there are one or more electrodes between the cathode and the anode a plurality of constant voltages can be taken off; the intermediate electrodes on one side serve as an anode and on the other side as a cathode.

A drawback from which stabilisation tubes often suffer consists in that, after the current has been substantially constant for a considerable time and is then brought to a higher value in a short time, the discharge spreads with difficulty over the cathode surf-ace. Sometimes this diiilcult spreading of the discharge is also manifest when the current is made to exceed a definite value. In these cases the voltage usually increases to a fairly high value and often oscillations occur, because the discharge jumps from one spot to the other.

To meet the aforesaid drawbacks in stabilisation tubes these tubes are,'according to the invention, equipped with a cathode (s) polished from the anode. The surface of an anodically polished plate is extremely smooth and, in contradistinction to a mechanically polished surface, exhibits no polishing scratches at all. In addition the undulations of the material are conserved, as a result of which the surface, especially when observing it under a sharp angle, exhibits a certain moir.

Anodicalpolishing has been known in allied arts for other purposes, e. g. for mural decorations with narrow strips of rust-resistant steel. However, the process of anodical polishing has not as yet been applied to cathodes of stabilisation and other glow discharge tubes. According to the invention, however, it has been found that anodically polished cathodes improve the performance of those tubes, i. e., it has been found that the discharge preferably settles at those points on the cathode surface having a high lustre.

preference of the discharge for definite points of the cathode surface may perhaps be explained by the fact that there are less impurities such as fat and oxides at these points so that the cathode drop is lower. This difference in surface conditions may already exist directly after manufacture or also as a result of a definite part of the cathode being cleaned by the discharge. To obtain a uniform surface of the cathode it is often electrolytically coated with a suitable metal layer. In this way, for instance, cathodes made from rolled sheet nickel are nickel-plated. This treatment, however, is comparatively expensive and usually the surface is not thoroughly clean. In addition, cracks often appear in the applied layer and it may even partly or entirely scale oif. With a surface polished from the anode the discharge has no preference spot at all so that an increase in current does not entail difliculties on account of an increase in voltage or oscillations. In the case of nickel cathodes sulphuric acid is a particularly suitable electrolyte for polishing from the anode. The current density is preferably between 0.2 and 2A./cm. the time being chosen between 1 second and 1 minute.

The invention will now be more fully explained by giving an example.

A cylinder rolled from sheet nickel and having a Wall thickness of 0.3 mm., a length of 5 cm. and a diameter of 2 cm. is suspended as an anode in a bath of strong sulphuric acid obtained by diluting one half concentrated sulphuric acid having a specific weight of 1.84. The cathode is fit in the cylinder so that the current practically flows solely on the inner side of the cylinder. A current of 20 amp. is sent through the bath for 40 seconds with the result that the anode is polished and exhibits a beautiful bright lustre, which is not feasible by any other mechanical polishing method.

A voltage stabilisation tube in accordance with the invention is shown in the accompanying drawing.

Such a tube comprises the usual envelope, an anodically polished nickel cathode (polished in accordance with the foregoing described pro cedure), an anode, and a dual electrode interposed between anode and cathode, one surface of which is anodically polished nickel and serves as an auxiliary or additional cathode, and the 3 other surface of which faces the first cathode serving as an anode.

What I claim is:

A voltage stabilisation tube, comprising an envelope and an electrode system therein including an electrode having a cathode surface and anode surface, the cathode surface having a mirror-like finish devoid of surface scratches and imperfections.

FREDERICUS ANTONIUS VAN BECKUM.

REFERENCES CITED The following references are of record in the file of this patent:

4 UNITED STATES PATENTS Name Date Laise Jan. 18, 1927 Geffcken et a1 Oct. 15, 1935 Lindh Jan. 31, 1939 Pomfrett Mar. 19, 1940 Allen June 11, 1940 Delaplace et al Aug. 25, 1942 Reyling Jan. 12, 1943 Atlee Sept. 14, 1943 

